Internal joint stabilizer device, system and method of use

ABSTRACT

A device is provided including a rotating portion that can be attached to a plate affixed to a first bone forming a joint and a portion that can be affixed to a second bone of the joint. The device is placed internally in order to prevent pin tract problems and to stabilize the joint while allowing motion of the joint along its natural trajectory. Additionally, a method for using the device is provided that includes attaching the rotating portion to a plate attached to a first bone forming a joint, and attaching the fixable portion to a second bone of the joint.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to: co-pending ProvisionalPatent Application No. 61/239,281, filed Sep. 2, 2009, entitled“Internal Joint Stabilizer And Method Of Use”; and is acontinuation-in-part of U.S. patent application Ser. No. 12/534,595,filed on Aug. 3, 2009, entitled “Internal Joint Stabilizer And Method OfUse”; which application claims priority from Provisional PatentApplication No. 61/085,651, filed on Aug. 1, 2008; Provisional PatentApplication No. 61/094,228, filed on Sep. 4, 2008; Provisional PatentApplication No. 61/100,138, filed on Sep. 25, 2008; Provisional PatentApplication No. 61/139,274, filed on Dec. 19, 2008, all entitled“Internal Joint Stabilizer And Method Of Use”; and from ProvisionalPatent Application No. 61/163,693, filed on Mar. 26, 2009 and entitled“Axis Locator Jig And Method”; all of the foregoing applications beingincorporated herein, by reference, in their entireties.

BACKGROUND OF THE INVENTION

The invention relates to the stabilization of joints for the purpose offacilitating healing and the early re-establishment of adequate range ofmotion at the joints.

DESCRIPTION OF THE RELATED ART

Dislocation and subluxation of joints are serious clinical problems thatif persistent, recurrent or chronic can result in irreversible damage.These chronic instabilities are usually the result of damage to thesupporting joint ligaments and/or the result of loss of bony integrity.Treatment of these conditions includes restoration of the properrelationships or “reduction” of the bones involved. Reduction must bemaintained for a period of time sufficient to allow for healing of thedamaged tissues. Also, it is desirable to maintain joint motion duringthis period in order to prevent ankylosis and to maintain a healthyarticular cartilage. Thus, the ideal immobilization for a dislocated orsubluxed joint would prevent abnormal translational movements but allowmotion similar to its normal kinematics.

Hinged external fixators have been devised for the purpose of allowingthe desired motion in the joint after reduction of the dislocation.These external fixators have been used primarily on the elbow but canalso be used on the knee or the ankle. Hinged external fixators haveprovided satisfactory end results, allowing patients to regain adequaterange of motion as well as stability of the joint. However, despitebeing considered “external” devices the installation of hinged externalfixators require open surgery in order to properly identify the axis ofrotation of the joint, a critical aspect of their functionality, becauseit has proven difficult or impossible to determine such axis fromoutside the body. Surgery, open or percutaneous, is also required toaffix the position of the installed hinged external fixator by insertingmultiple pins into the adjacent bones.

The intrinsic bulkiness of external fixators, combined with pain andfrequent complications at the pin tracts have limited the quality of theclinical results of these devices. Patients have difficulty in activelymoving these joints primarily due to pain in the pin tract sites.Patients are also limited in carrying out everyday functions due to thecumbersome nature of the device which must remain installed for arelatively long time, normally five or six weeks on average.

The need remains for a device that will maintain reduction whileallowing early post-operative normal motion of the joint but that willeliminate the problems of device bulkiness and pin tract pain andcomplications associated with existing hinged external fixators.

There additionally exists a need for a guide, system and method forlocating the axis of rotation of a joint, prior to stabilization andfor, subsequently, affixing a joint stabilizer.

BRIEF SUMMARY OF THE INVENTION

It is accordingly an object of this invention to provide an internaljoint stabilizer device, system and method which overcomes theabove-mentioned disadvantages of the heretofore-known devices. In oneparticular embodiment of the invention, a joint stabilizer device isprovided including a rotating portion that can be attached to a plateaffixed to a first bone of a joint and a portion that can be attached toa second bone of the joint. The device is placed internally in order toprevent pin tract problems and to stabilize the joint while allowingmotion of the joint along its natural trajectory.

Additionally, a method for using the device is provided that includes,in one particular embodiment of the invention, attaching a rotatingportion of an internal joint stabilizer device to a plate affixed to afirst bone forming a joint, and attaching a fixable portion to a secondbone of the joint. In another embodiment of the invention, a trajectoryguide is used to locate the axis of rotation of the joint, prior tostabilization.

Although the invention is illustrated and described herein as embodiedin an Internal Joint Stabilizer Device, System and Method, it isnevertheless not intended to be limited to the details shown, sincevarious modifications and structural changes may be made therein withoutdeparting from the spirit of the invention and within the scope andrange of equivalents of the claims.

The construction of the invention, however, together with additionalobjects and advantages thereof will be best understood from thefollowing description of the specific embodiment when read in connectionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are perspective views of two different particularembodiments of an internal joint stabilizer of the instant invention.

FIG. 2 is a perspective view of the internal joint stabilizer of FIG. 1Awith bone screws attached.

FIG. 3 is a perspective view of the internal joint stabilizer of FIG. 2after it has been installed in the humero-ulnar joint. FIG. 3A is anenlarged detail view of the humero-ulnar joint of FIG. 3.

FIG. 4 is a plan view of the internal joint stabilizer after it has beeninstalled in an interphalangeal joint.

FIG. 5 is a side elevational view of the internal joint stabilizer ofFIG. 4 after it has been installed in an interphalangeal joint.

FIG. 6 is an exploded perspective view of an exemplary joint includingan internal joint stabilizer of the instant invention used in conjuctionwith a prosthetic implant, in accordance with a further embodiment.

FIG. 7 is a side elevational view of an exemplary joint including theinternal joint stabilizer of FIG. 6 after installation.

FIG. 8 is a perspective view of a further particular embodiment of theinternal joint stabilizer of the instant invention.

FIG. 9 is an exploded perspective view of the internal joint stabilizerof FIG. 8.

FIGS. 10A and 10B are enlarged side elevation views of the plate portionof the internal joint stabilizer of FIG. 8.

FIGS. 11A and 11B are enlarged perspective views of the plate portion ofthe internal joint stabilizer of FIG. 8.

FIGS. 12A, 12B, 12C, 13A and 13B are enlarged perspective views of theturret portions of the internal joint stabilizer of FIG. 8.

FIG. 14 is a partially exploded perspective view of selected portions ofthe internal joint stabilizer of FIG. 8.

FIGS. 15A-15B are side elevational views, and FIGS. 15C-15D are explodedperspective views, of selected portions of the internal joint stabilizerof FIG. 14.

FIG. 16 is a perspective view of the internal joint stabilizer of FIG. 8indicating the different types of adjustment capabilities.

FIGS. 17A and 17B are perspective and exploded perspective views of afurther embodiment of the plate portion and turret assembly of theinternal joint stabilizer of FIG. 8.

FIGS. 18A-18B are a perspective view and an exploded perspective view,respectively, of selected portions of an internal joint stabilizer inaccordance with a further embodiment of the instant invention.

FIG. 18C is a perspective view of an internal joint stabilizer using theselected portions shown in FIGS. 18A-18B.

FIG. 19 is a side elevational view of an axis trajectory guide and itscomponent parts, in accordance with one particular embodiment of thepresent invention and FIG. 20 is an exploded view of the axis trajectoryguide of FIG. 19.

FIGS. 21-27 illustrate one particular method of using the axistrajectory guide of FIG. 19.

FIG. 28 is a perspective view of an internal joint stabilizer installedin a joint in accordance with another embodiment of the invention.

FIG. 29 is a plan view of a portion of the internal joint stabilizer andjoint of FIG. 28.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the figures of the drawings in detail and, moreparticularly, to FIGS. 1A and 2, there is shown one particularembodiment of an internal joint stabilizer 1 in accordance with thepresent invention. The internal joint stabilizer 1 is designed to beplaced internally, so as to prevent pin tract problems and to stabilizethe joint, while allowing motion at the joint along its naturaltrajectory.

The internal joint stabilizer 1 of FIG. 1A, is particularly adapted foruse in connection with hinged joints, such as an elbow, and ispreferably made of metal (such as titanium, cobalt chrome or stainlesssteel or a combination of titanium portions and cobalt chrome portions);bioabsorbable material (such as PLA or PGA) or a combination of metaland bioabsorbable material. The internal joint stabilizer 1 includes aplate portion 2, which is, preferably, formable (i.e., bendable).Extending through the plate portion 2 are holes 3 and 4, which areadapted to receive bone screws 7 and 8. Note that the holes 3 and/or 4can be embodied by a slot and that none, more or fewer holes 3 and/or 4to receive bone screws 7, 8 can be included in the plate portion 2, asdesired. The bone screw 7 is preferably a compression screw to beattached to a bone through hole or slot 3. If provided, holes 4 arepreferably adapted to receive, indiscriminately, compression screwsand/or angle-stable screws 8 to be attached to the same bone as screw 7,at an angle selected by the surgeon. If selected, angle-stable screws 8become engaged with holes 4 upon fully setting, providing furtherstability at the selected angle. Note that, as shown more particularlyin FIG. 1B, an internal joint stabilizer in accordance with the instantinvention can have a very simple form. For example, the entire internaljoint stabilizer 1′ of FIG. 1B, including the fixable portion 2′, holes3′, neck portion 5′ and axle portion 6′ can be made from a section ofK-wire or a Steinmann pin, for example, partially pre-bent to form, atleast, holes 3′ configured to receive compression and/or angle stablescrews and still be within the scope of the instant invention.

Referring now to FIGS. 4 and 5, there is shown another particularembodiment of an internal joint stabilizer 11 in accordance with thepresent invention. The internal joint stabilizer 11 is designed to beplaced internally, so as to prevent pin tract problems and to stabilizethe joint, while allowing motion at the joint along its naturaltrajectory.

The internal joint stabilizer 11 of FIGS. 4, 5 is particularly adaptedfor use in connection with other hinged joints, such as theinterphalangeal joints of the hand known as PIP (proximalinterphalangeal joint), DIP (distal interphalangeal joint) and IP(interphalangeal joint of the thumb), and is preferably made of metal(such as titanium, cobalt chrome or stainless steel), bioabsorbablematerial or a combination of both. The internal joint stabilizer 11includes a plate portion 12 which is preferably formable. Extendingthrough the plate portion 12 are hole or slot 13 and holes 14, which areadapted to receive bone screws 17 and 18. Note that none, fewer or moreholes 14 to receive bone screws 18 can be included in the plate portion12, as desired. The bone screw 17 is preferably a compression screw tobe attached to a bone through hole or slot 13. If provided, holes 14 arepreferably adapted to receive, indiscriminately, compression and/orangle-stable screws 18 to be attached to the same bone as screw 17, atan angle selected by the surgeon. If selected, angle-stable screws 18become engaged with holes 14, upon fully setting, providing furtherstability at the selected angle.

Referring now to FIGS. 1A, 2, 4 and 5 the internal joint stabilizer 1,11 additionally includes a neck portion 5, 15 extending from the edge 2a, 12 a of the plate portion 2, 12. An axle portion 6, 16 extends fromthe end of the neck portion 5, 15 distal from the plate 2, 12. The neckportion 5, 15 is preferably formable (i.e., bendable) such that it canbe formed by the surgeon intraoperatively in any of three axes X, Y, Zto conform to the anatomy of the patient after the axle portion 6, 16has been placed in alignment with the natural axis of rotation of thehinged joint where it is being used. As an example, in the case wherethe hinged joint is the elbow, the plate portion 2 would be rigidlyaffixed to the ulna on its lateral, posterior or its medial aspect,while the axle portion or projection 6 would project through a hole inthe humerus, aligned to the natural axis of joint rotation. In anotherexample, in the case where the hinged joint is an interphalangeal joint,the plate portion 12 would be rigidly affixed to the more distal phalanxon its ulnar or radial aspect, while the axle portion or projection 16would project through a hole in the more proximal phalanx, aligned tothe natural axis of joint rotation. It should be noted that therelationship between the plate portions 2, 12 and neck portions 5, 15 ofinternal joint stabilizers 1, 11 have been adapted to the anatomy towhich the internal joint stabilizer is being applied. In the case ofinternal joint stabilizer 1 the axis of the neck portion tends to besubstantially perpendicular to the axis of the plate portion (i.e.forming an inverted T) while in the case of internal joint stabilizer 11the axis of the neck portion tends to be substantially in line with theaxis of the plate portion. The relationship between the plate portionand the neck portion can be further adapted for other parts of theanatomy where the internal joint stabilizer will be applied whilestaying within the scope of the present invention.

The plate portion 2, 12 and neck portion 5, 15, respectively, of theinternal joint stabilizer 1, 11 could be constructed in accordance withthat described in U.S. patent application Ser. No. 12/463,037, whichapplication is being incorporated herein, by reference, in its entirety.

One particular method of utilizing the internal joint stabilizer 1 willnow be described in connection with FIGS. 1A-3A. More particularly,FIGS. 3-3A illustrate the internal joint stabilizer 1 attached to thehumero-ulnar joint. It can be seen that the axle portion 6 (shown indotted line) has been inserted into the humerus 20, in alignment withthe natural axis of rotation of the humero-ulnar joint. The plateportion 2 is attached to the ulna 21 (in this example, on the lateralside) using the bone screw 7, in compression mode, while the screws 8further attach the plate portion 2 to the ulna 21 in compression or inangle-stable mode. Additionally, the radius bone 22 is shown forreference only, since it is not affected by the procedure.

Furthermore, FIGS. 4 and 5 illustrates the internal joint stabilizer 11attached to an interphalangeal joint (a PIP joint, in particular). Itcan be seen that the axle portion 16 (shown in dotted line) has beeninserted into the more proximal phalanx 30, in alignment with thenatural axis of rotation of the interphalangeal joint. The plate portion12 is attached to the ulnar (shown) or the radial aspect of the moredistal phalanx 31 using the bone screw 17, in compression mode, whilethe screws 18 further attach the plate portion 12 to the more distalphalanx 31 in compression or in angle-stable mode.

To install the internal joint stabilizer the surgeon approaches theaffected joint through lateral and/or medial incisions (in the case ofthe elbow) or radial and/or ulnar incisions (in the case of theinterphalangeal joint). The dislocated joint is reduced and a firstpoint on the axis of rotation of the joint determined. This can beaccomplished by visual inspection of the anatomy. Alternatively, thejoint can be moved through its range of motion allowing the surgeon toidentify and mark the isometric point on the proximal bone of the joint(the humerus in the case of the elbow or the more proximal phalanx ofthe affected joint in the case of an interphalangeal joint) whichlocates a first point on the axis of rotation. In the case of the elbowthis point is located in the center of the capitellum next to the baseof the lateral epicondyle. Similarly, a second point on the axis ofrotation on the opposite side of the proximal bone 20, 30 of the jointcan be identified by fluoroscopy, direct inspection or with the aid of aspecialized axis trajectory guide (for example, the axis trajectoryguide 400 of FIG. 19) and marked. A hole is then drilled through theaxis of rotation in preparation for installation of the internal jointstabilizer.

The axle portion 6, 16 is then inserted in the hole drilled in theproximal bone of the joint. If and as required, the neck portion of theinternal joint stabilizer is then formed by the surgeon in such a waythat hole or slot 3, 13 of the plate portion 2, 12 will lie in itsproper position, flat against the relatively flat portion of the lateral(shown), posterior or medial aspect of the ulna 21 in the case of theelbow or the radial or ulnar (shown) aspect of the more distal bone ofthe affected joint 31 in the case of an interphalangeal joint. A bonescrew 7, 17 is inserted into hole or slot 3, 13 and screwed into thebone. If holes or slots 4, 14 are provided, the plate portion 2, 12 isfurther formed by the surgeon, as required, so that holes or slots 4, 14lie approximately flat against the lateral (shown), posterior or medialaspect of the ulna 21 in the case of the elbow or the radial or ulnar(shown) aspect of the more distal bone of the affected interphalangealjoint. Compression or angle-stable screws 8, 18 are then inserted intoholes 4, 14 at an angle selected by the surgeon and screwed into theulna 21 or phalanx 31 as the case may be. If desired, after screws 8, 18have been attached, the bone screws 7, 17 that were originally affixedthrough holes or slots 3, 13 may be removed and substituted byangle-stable screws 8, 18.

Range of motion and stability of the joint is again tested. Incisionsare closed by the surgeon in standard fashion.

If required, internal joint stabilizers made of metal may be removedsurgically after a period of time sufficient to allow healing of thedamaged tissues. In an alternate embodiment all or some portions of thestabilizer or, at least, its axle portion would be made of bioabsorbablematerial, i.e.: polylactic acid, thus reducing the need for surgicalremoval of some or all portions of the internal joint stabilizer.

Referring now to FIGS. 6 and 7, there is shown a further embodiment ofan internal joint stabilizer 40 in accordance with the instantinvention. In certain cases, the surface or end of the proximal bone 50of the joint may be damaged, and may need to be replaced. As such, inaccordance with the principles of the present invention, an axle portion42 of the internal joint stabilizer 40 of the present invention can beinserted into a prosthetic implant 60 inserted into the damaged proximalbone 50. For example, as shown in FIGS. 6 and 7, the internal jointstabilizer 40 is particularly adapted for use in the cases where thearticular surface of the proximal bone 50 (in this case, the humerus ofthe humero-ulnar joint) is damaged and needs to be replaced by aprosthetic implant 45. Note that the exemplary use of the humero-ulnarjoint is not meant to be limiting, as the use of the internal jointstabilizer 40 can be adapted for use in other joints (for example, inthe PIP joint) when the use of a prosthetic implant is indicated.

As shown more particularly in FIG. 6, in the present example, aprosthetic implant 45 is provided that includes a surface 45 a toreplace the damaged articular surface of the humerus 50 and a shaft 45 bto be inserted into, and affixed to, the medullary cavity 50 a of thehumerus 50. The prosthetic implant also includes a pre-drilled hole 46sized to receive the axle portion 42 of the internal joint stabilizer40. Alternatively, the surgeon may drill the hole 46 for the axle 42intra-operatively. Optionally, a bearing sleeve 48 preferably made ofplastic material can be provided to be inserted into the hole 46 of theprosthetic implant prior to inserting the axle 42 of the internal jointstabilizer 40. When using the optional bearing sleeve, the hole 46 inthe prosthetic implant 45 will be sized and otherwise configured toreceive the bearing sleeve 48.

To install the internal joint stabilizer shown in FIGS. 6 and 7, thesurgeon approaches the affected joint (i.e., the elbow in theillustrated example) through an incision and proceeds to remove thedamaged articular surfaces of the proximal bone 50 (for example, thehumerus) as shown in FIG. 6, to prepare the medullary cavity 50 a of theproximal bone 50 to receive the shaft 45 b of the prosthetic implant 45.The prosthetic implant 45 is then inserted and affixed with screwsand/or cement and/or other means to the proximal bone 50, such that theaxis of the hole 46 is aligned with the natural axis of rotation of theproximal bone 50.

The axle portion 42 is then inserted into the hole 46 in the prostheticimplant 45. Alternately, if provided, the optional bearing sleeve 48 maybe inserted into an appropriately sized hole 46 in the prostheticimplant 45 prior to inserting the axle portion 42 through a hole 48 ainto the bearing sleeve 48.

Once the axle portion 42 and/or bearing sleeve 48 and axle portion 42has been inserted into the hole 46 in the prosthetic implant 45, thesurgeon proceeds with the operation by following the steps previouslydescribed above in connection with the internal joint stabilizers ofFIGS. 1-5.

Referring now to FIGS. 8-11B, there is shown another embodiment of aninternal joint stabilizer 110 in accordance with the instant invention.The internal joint stabilizer 110 includes additional componentsdirected towards providing additional degrees of adjustability. Thepresent particular embodiment of the internal joint stabilizer 110includes a plate portion 120, a turret assembly 130, a neck portion 150,a swivel joint 170, an eyelet 171 and an axle portion 160. All componentportions of the internal joint stabilizer 110 but, at least, neckportion 150 and axle portion 160 can be provided in different sizes toaccommodate the particular anatomy of the patient.

In particular, the internal joint stabilizer 110 includes a plateportion 120 which, in the preferred embodiment, is bendable (i.e.,formable) intraoperatively. The plate portion defines an interiorsurface 121, configured to engage a bone, and an exterior surface 122,opposite the interior surface 121. As shown more particularly in FIG.10B, the plane of the exterior surface 122 is preferably chosen to beoblique to the plane of the interior surface 121, diverging fromparallel by an angle A1 in the range of 0>A1>=45 degrees. However, ifdesired, another angle can be chosen or the surface 122 may be selectedto be parallel to the surface 121.

As can be seen more particularly from FIGS. 11A and 11B, at least twoholes 123 extend through the plate 120, between the interior surface 121and the exterior surface 122. Holes 123 are adapted to receive afixation device therethrough, for example, compression bone screws (124of FIG. 10A) or angle-stable bone screws (not shown). In one particularembodiment, the perimeter surrounding the screw holes 123 on theinterior surface 121 of the plate can be provided with protrusions 125that enhance frictional engagement with the bone. Additionally, a turrethole 126 extends through the plate 120, between the interior surface 121and exterior surface 122. Turret hole 126 includes a circumferential lip127 and is adapted to receive a turret assembly (130 of FIG. 9). Asshown in FIGS. 11A and 11B the turret hole 126 defines an axis Y-Y′,perpendicular to exterior surface 122, around which the turret assembly(130) can rotate.

Referring now to FIGS. 11A to 14B, there will be described a turretassembly 130 for use with one particular embodiment of the presentinvention. Turret assembly 130 includes a turret portion 131, a turretnut portion 132 and a turret set screw 133. The turret portion 131 isdimensioned to be inserted into the turret hole 126 of the plate 120,from the side of the exterior surface 122, until it is engaged with(i.e., seated against the exterior wall of) the circumferential lip 127.The turret nut portion 132 is dimensioned to be inserted into the turrethole 126 from the side of the interior surface 121 of the plate 120until it is seated against the interior surface of the circumferentiallip 127. The turret portion 131 and the turret nut portion 132 areprecisely dimensioned to fit inside their respective sides of the turrethole 126 while allowing sufficient clearance to permit their rotationinside the turret hole 126 around the axis Y-Y′ (RT′ of FIG. 14). Theturret portion 131 and turret nut portion 132 are fixed looselytogether, each on its respective side of the circumferential lip 127, bythe turret set screw 133, with the lip portion 134 of the turret portion131 disposed therebetween. The lip portion 134 of the turret assembly130 is designed to loosely engage the circumferential lip 127 and permitrotation of the turret assembly 130. Further tightening of the turretset screw 133 draws the turret nut portion 132 into frictionalengagement with the circumferential lip 127, thereby impeding furtherrotation of the turret assembly 130.

Referring now to FIGS. 12A-14, it can be seen that the turret portion131 is provided with a hole 135, dimensioned to receive and frictionallyengage with a neck portion 150. Hole 135 is preferably cylindrical withits centerline defining an axis Z-Z′. As additionally shown, in thepresent embodiment, the turret portion 131 also includes a slot 136 tofacilitate clamping of neck portion 150 to turret portion 131 upontightening of turret set screw 133. The slot 136 is parallel to the axisZ-Z′ and extends through a portion of the turret portion 131, from oneend of the hole 135 to the other end of the hole 135. Correspondingly,the neck portion 150 has a cylindrical cross-section and is dimensionedto be inserted, at least partially, into the cylindrical hole 135. Onceinserted, neck portion 150 can rotate about the axis Z-Z′ (RT of FIG.14) within the cylindrical hole 135. Neck portion 150 can also slideablytranslate longitudinally along axis Z-Z′ of hole 135 (TR of FIG. 14).However, once turret screw 133 is fully tightened into the turret nutportion 132, friction between hole 135 and neck portion 150 clamps neckportion 150 and impedes any further rotational or translational movementof the neck portion 150 within the hole 135. The mechanism for clampingthe neck portion 150 described above is not intended to be limited tothe details shown since other methods of clamping can be used withoutdeparting from the spirit of the invention and within the scope andrange of equivalents of the claims.

As shown more particularly in FIGS. 14-15B, a swivel joint 170 can alsobe provided, permitting rotation of the neck portion 150 around the axisX-X′ (RT″ of FIG. 14), while swivel joint screw 151 is loosely attached.More particularly, rotation of the swivel joint 170 allows the angulardisplacement of neck portion 150 relative to axis W-W′ of axle portion160 after such axle has been threadably attached to eyelet 171 of swiveljoint 170. Rotation of swivel joint 170 can be impeded by fullytightening swivel joint screw 151.

Referring now to FIGS. 15A-15D, FIGS. 15A and 15B show exemplarytranslational displacements of neck portion 150 in the turret assembly130. For example, FIG. 15A shows the neck portion 150 as fully insertedinto the turret assembly 130 while FIG. 15B shows neck portion 150 fullyextended above the turret assembly 130. FIGS. 15C-15D illustrate afurther embodiment of swivel joint 170 where it can be observed that thecorresponding surfaces of swivel joint 170 can be matchingly splined(i.e., “grooved”) on the surfaces 173, 174 (as seen in FIG. 15C) orsplined on one surface 173 and ridged circumferentially with adeformable (softer) metal on the other surface 175 (as seen in FIG. 15D)to advantageously allow the swivel joint to be fixed at any desiredangle. In a still further embodiment it can be seen in FIG. 15D thatneck portion 150′ is totally straight, that is, totally aligned withaxis Z-Z′ as opposed to neck portion 150 (FIG. 15A-15B) that ispartially straight and partially curved and where only the straightportion aligns with axis Z-Z′. Additionally, the lower end of neckportion 150, 150′ can be grooved longitudinally with grooves 152 whichprovide increased friction with hole 135 and allow for burr-free cuttingif, after installation, neck portion 150, 150′ protrudes more thandesired below turret portion 131.

Referring now to FIG. 16, the internal joint stabilizer 110 described inconnection with FIGS. 8-15C, provides 4 degrees of freedom foradjustment: a.) rotation of neck portion 150, 150′ around axis Z-Z′(RT); b.) longitudinal translation of neck portion 150, 150′ along axisZ-Z′ (TR); c.) rotation of turret assembly 130 around axis Y-Y′ (RT′)with resulting angular displacement of neck portion 150, 150′; and d.)angular displacement of neck portion 150, 150′ relative to axle portionaxis W-W′ resulting from rotation of swivel joint 170 around axis X-X′(RT″).

Referring now to FIGS. 17A and 17B, there is shown a further embodimentof a plate portion and turret assembly for use with an internal jointstabilizer of the instant invention. For example, if desired, the plate201 and turret assembly 200 of FIGS. 17A-17B can be substituted for theplate 120 and turret assembly 130 in the internal joint stabilizer 110of FIGS. 8-16. More particularly, the plate 201 and turret assembly 200are configured to provide the internal joint stabilizer of the instantinvention with an additional degree of freedom for adjustment. As shown,turret assembly 200 includes a cylindrical hole 290, therethrough, whichdefines an axis V-V′. The cylindrical hole 290 receives acorrespondingly sized cylindrical shaft portion 280, extending betweenthe two plate sockets 295. Each plate socket 295 includes a screw hole123 and can include protrusions 125, similar to those previouslydescribed in connection with the plate 120 of FIGS. 8-16. As also shownin FIG. 17B, the turret assembly 200 can be used with turret portion131, turret nut portion 132 and turret set screw 133, of the previouslydescribed turret assembly 130. The turret assembly 200 can additionallymate with a neck portion 150, 150′ in the manner described in connectionwith FIG. 14 above.

When plate portion 201 and turret assembly 200 are used as part of aninternal joint stabilizer, such as the internal joint stabilizer 110 ofFIG. 8, an additional (fifth) degree of freedom is advantageouslyobtained. More particularly, this further degree of freedom permitsrotation of the turret assembly 200 around axis V-V′ (RT″ of FIG. 17B),resulting in a further corresponding rotation of a connected neckportion 150, 150′.

Referring now to FIGS. 18A and 18B, there is shown a further embodimentof a plate portion and turret assembly for use with an internal jointstabilizer of the instant invention. For example, if desired, the plate301 and turret assembly 300 of FIGS. 18A-18B can be substituted for theplate 120 and turret assembly 130 in the internal joint stabilizer 110of FIGS. 8-16. More particularly, the plate 301 and turret assembly 300are configured to provide the internal joint stabilizer of the instantinvention with one more additional degree of freedom for adjustment asthat provided by the plate 201 and turret assembly 200. As shown, turretassembly 300 includes a cylindrical hole 390, therethrough, whichdefines an axis V-V′. The cylindrical hole 390 receives a cylindricalshaft portion 380 of corresponding diameter but of greater length thancylindrical hole 390, extending between the two plate extensions 395.Plate 301 includes a screw holes 123 similar to those previouslydescribed in connection with the plate 120 of FIGS. 8-16 and a slot 323configured to receive a compression screw. As also shown in FIG. 18B,the turret assembly 300 includes turret portion 331, turret nut portion332 and turret set screw 333, similar to previously described turretassembly 130. The turret assembly 300 can additionally mate with a neckportion 150, 150′ along axis Z-Z′ in the manner described in connectionwith FIG. 14 above.

When plate portion 301 and turret assembly 300 are used as part of aninternal joint stabilizer, such as the internal joint stabilizer 110 ofFIG. 8, an additional (sixth) degree of freedom is advantageouslyobtained. More particularly, this further degree of freedom permitslongitudinal translation of the turret assembly 300 along axis V-V′ (TR′of FIG. 18A), resulting in a further possible adjustment of a connectedneck portion 150, 150′.

FIG. 18C shows internal joint stabilizer 310, which includes plateportion 301, turret assembly 300, neck portion 150′, swivel joint 170and axle portion 160 described above after installation on the posteriorpart of the ulna 21 in the humero-ulnar joint. It should be noted thatthe humerus 20 is shown semi-transparent to permit visualization of theaxle portion 160 through the axis of rotation of the joint, while theulna 21 and the radius 22 are shown solid.

To install an internal joint stabilizer of the instant invention, suchas the internal joint stabilizer 110 of FIG. 8 or 310 of FIG. 18C, thesurgeon approaches the elbow through a lateral or a medial incision. Afirst point on the axis of rotation is determined and marked. This canbe accomplished by visual inspection of the anatomy. Alternatively, thejoint can be moved through its range of motion allowing the surgeon toidentify and mark the isometric point on the humerus which locates afirst point on the axis of rotation. This point is located at the centerof the capitulum, next to the base of the lateral epicondyle. Similarly,another end point of the axis of rotation on the opposite side of thehumerus can be identified by fluoroscopy, direct inspection or with theaid of a guide (for example, the axis trajectory guide 400 of FIG. 19).A hole is then drilled connecting both end points of the axis ofrotation in preparation for installation of the internal jointstabilizer.

All portions of the internal joint stabilizer 110, 310 with theexception of axle portion 160 are loosely assembled. While keeping theturret set screw (133, 333 of FIGS. 14, 18B) and the swivel joint screw(151 of FIG. 14) loosely attached in order to allow relative movementbetween its different portions, the surgeon introduces the internaljoint stabilizer into the incision, while identifying an optimallocation (lateral, medial or posterior) for installing the plate portion120, 201, 301 to the ulna. The plate portion 120, 201, 301 is thenattached to the ulna with compression screws or with angle-stablescrews, as desired. The eyelet of the swivel joint (171 of FIG. 14) ismoved into contact with the humerus just opposite the entry point of thehole previously drilled in the humerus. An appropriately sized axleportion 160 is inserted through the eyelet 171 and into the previouslydrilled hole. Axle portion 160 is tightly screwed into the eyelet 171.The surgeon adjusts the longitudinal and angular position of the neckportion 150, 150′ by rotating and sliding along axis Z-Z′ and byrotating the turret portion (131 of FIG. 14 and FIG. 17B or 331 of FIG.18A-18B) and by adjusting the rotation of the swivel joint (170 of FIG.14). The swivel joint screw (151 of FIG. 14) and the turret set screw(133 of FIG. 14 and FIG. 17B or 333 of FIG. 18B) are tightened and rangeof motion is tested. If necessary finer adjustments are performed bysequentially loosening and tightening the turret set screw 133, 333and/or the swivel joint screw 151 until optimal range of motion isachieved. Incisions are then closed by the surgeon in standard fashion.

Referring now to FIGS. 19-27, therein will be described an axistrajectory guide and method that can, optionally, be used to locate theaxis of rotation of a joint, prior to stabilization using one of thedevices described in connection with FIGS. 1-18C. It is important tonote that the axis trajectory guide can be used as part of a system, incombination with the internal joint stabilizer devices described herein,but is not limited thereto. Rather, the axis trajectory guide of FIGS.19-27 can also be used to locate the axis of rotation of a joint for theinsertion of a known and/or different type of fixator or jointstabilizer or in any other situation when it is desired to locate theaxis of rotation of a joint.

In order to locate the axis of rotation of a joint, it is sufficient toidentify two points pertinent to the joint's rotation. Once identified,the axis of rotation for the joint can be represented by a straight linecontaining the two identified points.

For example, referring to the case of an elbow joint for illustrativepurposes only, the location of two pertinent points of rotation of thisjoint will permit the axis of rotation to be visualized. Approaching thehumero-ulnar joint through a lateral incision a surgeon can visuallyidentify one such point. This first point is located in the center ofthe capitulum next to the base of the lateral epicondyle. A second pointcan be assumed to be a point in the center line of the “spool” shapedtrochlea (the humeral portion of the ulnar-humeral joint). In order tolocate this point, a guide is provided herein, such as the axistrajectory guide 400 of FIG. 19, having an arcuate (i.e. in the shape ofan arc of a circle) portion that can be fitted over the trochlea toparticularly identify a second point on the axis.

The axis trajectory guide 400 of FIG. 19 will now be described, moreparticularly, in connection with FIGS. 19-20. Referring now to FIG. 19,there is shown an elevational view of an axis trajectory guide and itsprincipal component parts, in accordance with one particular embodimentof the present invention. FIG. 20 is a perspective exploded view of theaxis trajectory guide 400 of FIG. 19.

In particular, the axis trajectory guide 400 of FIGS. 19-20 includes ahandle portion 410, a center locator 420, and a removable alignmentsleeve 430 which is configured to receive a K-wire 440 of known lengthL. The handle portion 410 can be made from any desired material, but ispreferably made of metal, such as stainless steel, or plastic.

As shown more particularly in FIG. 20, the center locator 420 of theaxis trajectory guide 400 includes an arcuate distal portion 422defining a periphery. Please note that the arcuate distal portion of thecenter locator need not be limited to proscribing a particular arc of acircle. Rather, if desired, the partially open arcuate area defined canbe equal to a semi-circle, larger than a semi-circle as shown in FIG.20, or even smaller, as desired. Center locators 420 with differentdiameters of distal portion 422 can be provided to accommodate differentanatomies. The proximal end of the center locator 420 can be eitherfixed to (as shown), integrally formed with or, preferably, removablyattached to, a distal end 411 of the handle portion 410, thus, together,forming the body of the axis trajectory guide 400. Additionally, handleportion 410 is configured to receive the cannulated extension pinportion 434 of removable alignment sleeve 430 through opening 412located on the side of handle portion 410 which is opposite to thelocation of center locator 420. Note that, when adapted for use injoints other than the elbow, the distal portion of the center locator420 of the axis trajectory guide 400 would be, correspondingly,geometrically adapted to engage a portion of a bone in the joint andlocate the desired axis trajectory thereof.

The removable alignment sleeve 430 further includes a knob 431 having anopening 432 therethrough that further continues through cannulatedextension pin 434. The opening 432 is sized to receive a K-wire 440 ofknown length L or other type of longitudinally extending device, asshown more particularly in FIG. 20. As seen more clearly in FIGS. 26-27the cross-section of cannulated extension pin 434 is cylindricalthroughout approximately three quarters (%) of its perimeter, the lastquarter protruding slightly to form a cam. When the cam is in neutralposition as shown on FIGS. 26-27 the cannulated extension pin 434 canslide longitudinally along the axis of opening 412. By rotating knob 431clockwise the cam shaped cannulated extension pin 434 engages thecorrespondingly configured opening 412, locking it in place and therebyimpeding further longitudinal sliding of cannulated extension pin 434along the axis of opening 412.

The center locator 420, alignment sleeve 430 and K-wire 440 can be madeof any desired material, but, preferably, are made of metal, such asstainless steel.

A method for using the axis trajectory guide 400 of FIG. 19 will now bedescribed in connection with FIGS. 21-27 using an elbow joint, forillustrative purposes. The surgeon proceeds, as previously described, byapproaching the humero-ulnar joint through a lateral incision andmarking a first point 460 (as seen in FIG. 21) on the axis of rotationof the joint.

Referring now to FIG. 21, the surgeon distracts the humerus from theulna and inserts the center locator 420 into the distracted joint untilit “sits” on the humeral trochlea 455. The handle 410 is used tomanipulate the center locator 420 into the joint.

As shown in FIGS. 22-23, once the center locator 420 has been correctlyseated on the trochlea 455, the cannulated extension pin 434 of thealignment sleeve 430 is inserted into the opening 412 in the handleportion 410 of the axis trajectory guide 400 so that the distal end ofcannulated extension pin 434 is almost touching the first point 460previously marked by the surgeon on the humerus 450 but sufficientlydistant to allow visual observation of point 460. The surgeon then locksthe cannulated extension pin 434 in that position by turning knob 431clockwise.

As further shown in FIG. 24, once the alignment sleeve 430 has beenlocked within opening 412 of handle portion 410, the surgeon inserts aK-wire 440 of known length L until it engages the humerus 450 at firstmarked point 460.

Under fluoroscopy, the K-wire 440 is carefully drilled into the humerus450, while the surgeon visually ascertains that the K-wire 440 iscentered within the arcuate portion 422 of the center locator 420 andwhile taking care to drill to just beyond the distal edge of the arcuateportion 422 of the center locator 420 but short of the distal cortex ofthe humerus.

Referring now to FIGS. 24-25, subsequent to the placement of the K-wire440, the knob 431 on alignment sleeve 430 is turned counterclockwise torelease the cannulated alignment pin 434. The alignment sleeve 430 isfirst removed from opening 412 and then the remainder of axis trajectoryguide 400 is removed from the joint, while the K-wire 440 is left inplace. The K-wire 440 now defines the axis of rotation of the joint.Using a depth gauge (not shown) the surgeon measures the protrudinglength L2 of K-wire 440. Since the total length L of K-wire 440 isknown, the length L1 of K-wire 440 embedded in humerus 450 is calculatedand noted.

Thus defined, the axis of rotation of the subject joint, as locatedusing the axis trajectory guide 400 of FIGS. 18-26, can be used tofurther act on the subject joint. For example, the surgeon can use acannulated drill to insert over the K-wire 440 and create a cylindricalcavity of now known length L1 aligned to the natural axis of rotation ofthe joint and capable of accepting an axle portion 160 of, at most,length L1 of a joint stabilizing device.

The axis trajectory guide and method described herein can be used tolocate the axis of rotation of a joint in order to facilitate thestabilization of that joint utilizing an internal and/or external jointstabilizer. However, as noted above, this is not meant to be limiting,as the presently described guide and method can be used in any situationwherein it is desired to locate the axis of a joint, whether or not thejoint is subsequently stabilized.

It is advantageous to provide the axis trajectory guide described hereinas part of a kit including the internal joint stabilizer device, whereinthe kit can also include a plurality of axles and necks of differentlengths, to permit the surgeon to adapt an internal joint stabilizer tothe anatomy of the particular patient, intraoperatively. For example,after determining the length L1, the surgeon can select an axle having abody length shorter than, but closely approximating, the length L1 froma plurality of axles provided in the kit. Similarly, the surgeon canselect a neck portion, intraoperatively, from a plurality of necks ofdifferent lengths and shapes provided in the kit, order to accommodatethe particular anatomy of the patient. In such an embodiment, theselected neck can be further attached to one of a plurality ofadjustment portions, such as the different turret assemblies describedherein.

Referring now to FIGS. 28 and 29, there is shown an internal jointstabilizer 500 in accordance with a further embodiment of the presentinvention. The internal joint stabilizer 500 is designed to placedinternally, so as to prevent pin tract problems associated with externaldevices and to stabilize the joint, while allowing motion at the jointalong its natural trajectory.

The internal joint stabilizer (IJS) 500 of FIGS. 28-29 is particularlyadapted for use in connection with hinged joints, such as an elbow andis preferably made of metal, such as titanium or stainless steel. Theinternal joint stabilizer 500 of the instant embodiment includes all ofthe components of the IJS 300 of FIG. 18C, described hereinabove, butinstead of an axle (160 of FIG. 18C), the IJS 500 of the instantembodiment includes a rotating portion 520, such as a bearing or hinge,that is attached to a plate 510 (i.e., which is a humeral plate, in theinstant embodiment), which is affixed with screws to the surface,(lateral side surface shown in FIG. 28) of the humerus through holes 510a. The remaining portions of the IJS 500 of the instant embodiment wouldbe similar or identical to those like numbered portions shown anddescribed in connection with the IJS 300, above, and would be attachedto the ulna 21 as described above. In other words, in the IJS 500, thehumeral plate 510 and bearing 520 replace the axle portion 160 of theIJS 300 of FIG. 18C, which was physically inserted co-linearly with thenatural axis of rotation of the joint. With the IJS 500, the bearing 520acts as a “virtual” axle portion once it is aligned with the naturalaxis of rotation of the joint. The humeral plate 510 performs thefunction of holding the bearing 520 in the correct position.

The plate 510 is positioned such that the hinged/articulating portion520 can be placed on the axis of forearm rotation, defined as a line 530which runs through the center of the capitellum “C” and the trochlea“T”, as shown more particularly in FIG. 29. The axis 530 can be foundusing a center locator, such as the center locator 420 of the axislocator guide 400 described in connection with FIGS. 19-27, or by anyother method or system, as desired. Note that, if desired, the plate 510can be bendable to be adapted, interoperatively, to the shape of thehumerus.

In one particular embodiment of the IJS 500 has, at its distal end, abearing or other articulating means 520 that is configured to beattached to the humeral plate 510. Alternatively, the bearing or otherarticulating means 520 could be provided as part of the distal end ofthe humeral plate. If desired, the “eyelet” of the swivel joint (171 ofFIG. 14) of would be adapted and/or configured for fixed attachment tothe bearing 520. For example, in one particular embodiment, the eyelet171 of FIG. 14 would be replaced by a threaded portion that could beengaged with a thread in the bearing 520. Alternately, the eyelet 171can be replaced by a post terminating in a ball, which ball would engagea mating connector on the bearing 520. The connector should beconfigured to permit plate 510 to rotate about the ball, initially, soas to select an optimal position of the plate relative to the swiveljoint 170, but to include a locking mechanism that would impede furtherrotation about the ball, once the optimal position relative to thebearing 520 has been found.

Thus, in order to facilitate placing the center of rotation of thebearing collinearly with the axis of rotation of the humerus 20, theposition of the bearing should initially be adjustable in the X, Y and Zplanes.

Additionally, it is advantageous to lock the bearing 520 so that it canonly rotate on a plane perpendicular to the identified axis of forearmrotation. Again here, the previously referred to center locator could beused to align the bearing prior to locking. This adjustment would bemade at angles “alpha” and “beta” of FIG. 29.

The IJS 500 including the bearing 520 on the plate 510 would providestability in cases where an IJS with an axle is not indicated orsuitable.

Although described above in connection with the elbow and theinterphalangeal joints, this is not meant to be limiting, as otherinternal joint stabilizers and axis trajectory guides can be made inaccordance with the description herein, but of different size or scale,so as to treat instability, subluxation or dislocation of other joints,such as the ankle, or chronic instability such as occurs on the firstmetatarso-phalangeal joint or bunion. Additionally, it can be seen fromthe description herein that the internal joint stabilizer of the presentinvention can be adapted for use with joints having more complextranslational geometries, or more than one axis of rotation, such as thecarpometacarpal (CMC) joint of the thumb or the knee, wherein the devicewould be adapted to allow for the unique motions of these joints. Forexample, in one particular embodiment, the internal joint stabilizer ofthe present invention can be modified to further include more than oneaxle or linkage arms placed at the appropriate isometric points. Assuch, although the invention is illustrated and described herein invarious embodiments including an axle portion that is rotatable relativeto a fixable portion using various particularly described mechanisms,such as a bendable neck portion, a turret assembly and/or a swivelportion, etc., and/or as including a first plate portion, a rotatingbearing portion, an adjustable neck portion and a second plate portion,it is nevertheless not intended to be limited to only these detailsshown, since various modifications and structural changes may be madetherein without departing from the spirit of the invention and withinthe scope and range of equivalents of the claims.

1. An internal joint stabilizer comprising: a rotating portionconnectable to a first plate affixed to a first bone of a joint; saidrotating portion to be attached with its axis of rotation collinear withthe natural axis of rotation of the joint between the first bone and asecond bone; an adjustable neck portion; a second plate attached to saidneck portion; and said first plate portion having holes formed thereinfor receiving screws.
 2. The internal joint stabilizer of claim 1,wherein the rotatable portion is a bearing or hinge.
 3. The internaljoint stabilizer of claim 2, wherein the bearing or hinge is adjustablearound the X, Y and Z axes.
 4. The internal joint stabilizer of claim 1,wherein the adjustable neck portion includes a lockable swivel joint formoving the first plate relative to the second plate.
 5. A method ofjoint stabilization which comprises the following steps: providing aninternal device, including: a rotating portion attached to a firstplate; and a fixable portion; affixing the first plate to a first boneforming a joint with the rotating portion aligned collinearly with theaxis of rotation of the joint; and attaching the fixable portion to asecond bone of the joint.
 6. The method of claim 5, wherein the internaldevice further includes an adjustable neck disposed between the rotatingportion and the fixable portion.
 7. The method of claim 6, furtherincluding the step of adjusting the adjustable neck prior to attachingthe fixable portion to the second bone of the joint.
 8. The method ofclaim 5, wherein the rotatable portion is a hinge or bearing.
 9. Themethod of claim 8, wherein the bearing or hinge is adjustable around theX, Y and Z axes.
 10. The method of claim 5, further comprising the stepof moving the rotating portion prior to fixing the fixable portion tothe second bone.
 11. The method of claim 5, wherein a guide device isused to locate the axis of rotation of the joint during the affixingstep.
 12. The method of claim 11, wherein the affixing step includes thesteps of: identifying and marking a first point of rotation of thejoint; utilizing the guide device to identify the second point on theaxis
 13. The method of claim 12, wherein the identifying step includesthe step of visually identifying the first point.
 14. A system forstabilizing a joint, comprising: an internal joint stabilizer kit,including: an internal stabilizer including a rotating portion attachedto a first plate, a second plate, and an adjustable neck disposedbetween said first plate and said second plate; and a guide for locatingthe natural axis of rotation of the joint, said guide, including ahandle portion; a center locator attached to the handle portion, saidcenter locator forming a periphery; and an alignment sleeve having abore defined therethrough, such that an axis through said boreadditionally extends through the interior of said periphery.
 15. Thesystem of claim 14, wherein the periphery of the center locator is anarc of a circle.